// Copyright 2025 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package singlestoresql

import (
	"context"
	"database/sql"
	"fmt"
	"net/http"

	yaml "github.com/goccy/go-yaml"
	"github.com/googleapis/mcp-toolbox/internal/embeddingmodels"
	"github.com/googleapis/mcp-toolbox/internal/tools"
	"github.com/googleapis/mcp-toolbox/internal/util"
	"github.com/googleapis/mcp-toolbox/internal/util/parameters"
)

const resourceType string = "singlestore-sql"

func init() {
	if !tools.Register(resourceType, newConfig) {
		panic(fmt.Sprintf("tool type %q already registered", resourceType))
	}
}

func newConfig(ctx context.Context, name string, decoder *yaml.Decoder) (tools.ToolConfig, error) {
	actual := Config{ConfigBase: tools.ConfigBase{Name: name}}
	if err := decoder.DecodeContext(ctx, &actual); err != nil {
		return nil, err
	}
	return actual, nil
}

type compatibleSource interface {
	SingleStorePool() *sql.DB
	RunSQL(context.Context, string, []any) (any, error)
}

// Config defines the configuration for a SingleStore SQL tool.
type Config struct {
	tools.ConfigBase   `yaml:",inline"`
	Type               string                 `yaml:"type" validate:"required"`
	Source             string                 `yaml:"source" validate:"required"`
	Statement          string                 `yaml:"statement" validate:"required"`
	Parameters         parameters.Parameters  `yaml:"parameters"`
	TemplateParameters parameters.Parameters  `yaml:"templateParameters"`
	Annotations        *tools.ToolAnnotations `yaml:"annotations,omitempty"`
}

// validate interface
var _ tools.ToolConfig = Config{}

// ToolConfigType returns the type of the tool configuration.
func (cfg Config) ToolConfigType() string {
	return resourceType
}

// Initialize sets up and returns a new Tool instance based on the provided configuration.
// It processes tool parameters and constructs the necessary manifests for tool operation.
// Returns an initialized Tool or an error if setup fails.
func (cfg Config) Initialize(context.Context) (tools.Tool, error) {
	if cfg.Description == "" {
		return nil, fmt.Errorf("description is required for tool %q", cfg.Name)
	}

	allParameters, paramManifest, err := parameters.ProcessParameters(cfg.TemplateParameters, cfg.Parameters)
	if err != nil {
		return nil, err
	}

	return Tool{
		BaseTool: tools.NewBaseTool(
			cfg,
			tools.GetAnnotationsOrDefault(cfg.Annotations, tools.NewDestructiveAnnotations),
			tools.Manifest{Description: cfg.Description, Parameters: paramManifest, AuthRequired: cfg.AuthRequired},
			allParameters,
		),
	}, nil
}

// validate interface
var _ tools.Tool = Tool{}

// Tool represents a SingleStore SQL tool instance.
type Tool struct {
	tools.BaseTool[Config]
}

// Invoke executes the SQL statement defined in the Tool using the provided context and parameter values.
// It resolves template parameters and standard parameters, executes the query, and processes the result rows.
// Each row is returned as a map with column names as keys and their corresponding values, handling special
// cases for JSON and string types. Returns a slice of maps representing the result set, or an error if any
// step fails.
//
// Parameters:
//
//	ctx    - The context for controlling cancellation and timeouts.
//	params - The parameter values to be used for the SQL statement.
//
// Returns:
//   - A slice of maps, where each map represents a row with column names as keys.
//   - An error if template resolution, parameter extraction, query execution, or result processing fails.
func (t Tool) Invoke(ctx context.Context, resourceMgr tools.SourceProvider, params parameters.ParamValues, accessToken tools.AccessToken) (any, util.ToolboxError) {
	source, err := tools.GetCompatibleSource[compatibleSource](resourceMgr, t.Cfg.Source, t.Cfg.Name, t.Cfg.Type)
	if err != nil {
		return nil, util.NewClientServerError("source used is not compatible with the tool", http.StatusInternalServerError, err)
	}

	paramsMap := params.AsMap()
	newStatement, err := parameters.ResolveTemplateParams(t.Cfg.TemplateParameters, t.Cfg.Statement, paramsMap)
	if err != nil {
		return nil, util.NewAgentError("unable to extract template params", err)
	}

	newParams, err := parameters.GetParams(t.Cfg.Parameters, paramsMap)
	if err != nil {
		return nil, util.NewAgentError("unable to extract standard params", err)
	}

	sliceParams := newParams.AsSlice()
	resp, err := source.RunSQL(ctx, newStatement, sliceParams)
	if err != nil {
		return nil, util.ProcessGeneralError(err)
	}
	return resp, nil
}

// EmbedParams overrides BaseTool to apply the pgvector formatter.
func (t Tool) EmbedParams(ctx context.Context, paramValues parameters.ParamValues, embeddingModelsMap map[string]embeddingmodels.EmbeddingModel) (parameters.ParamValues, error) {
	return parameters.EmbedParams(ctx, t.StaticParameters, paramValues, embeddingModelsMap, embeddingmodels.FormatVectorForPgvector)
}

func (t Tool) ToConfig() tools.ToolConfig {
	return t.Cfg
}